In 2011 we are wondering about this question, as divorce rates have not changed that dramatically for almost 30 years. Fifty percent of all marriedcouples will trade in their spouse for a new model at least once and sometimes twice in their lifetime. And 35% to 50% of everyone will cheat at some point in their marriage. Why is it so difficult to stay married and monogamous?

The first reason is cultural. People now live longer than in previous centuries who may have been married for 10 to 15 years, and then died. Life expectancy used to be only till age 38 for the average man. It may sound easy to stay monogamous with someone for 10 years, but now couples are expected to stay sexually and emotionally connected to each other for 40, 50, even 60 years.

There is no precedent in any culture for staying married and passionate with the sameperson for that amount of decades. We aren't taught how to remain monogamous and happy with a single sexual partner for half a century, probably because we've never before had to be.

Studies show that monogamy may not be natural to our species, but is a conscious choice that couples have to make every day. Yet monogamy is perhaps the best choice for our species. A long-term, connected, monogamous relationship creates better parenting and encourages emotional creativity among human.

To remain monogamous and stay happy with the same person for many years,you have to learn certain relational skills, including self-control, empathy, frustration tolerance, patience, and simple kindness.

Marriage is a relationship that's continually being renegotiated--and its far better that we negotiate monogamy on a regular basis instead of taking it for granted. Sharing with each other often about your fears and concerns with honesty and sensitivity is a better way to manage happily ever after then merely wishing for a long life together riding off into the sunset....